Vinyl Hybrid Silica Nanoparticles Research Articles

Autonomous Chemistry Enabling Environment-Adaptive Electrochemical Energy Storage Devices

Autonomous Chemistry Enabling Environment-Adaptive Electrochemical Energy Storage Devices

Dual crosslinked ionogels with high stretchability and self-healing ability for wearable motion and thermal sensors

An effective strategy was proposed to fabricate high-performance ionogels in which the polymer chains were dual crosslinked by hydrogen bonding and vinyl hybrid silica nanoparticles. The synthesized dual crosslinked ionogels exhibit excellent stretchability and self-healing ability. The skin-type wearable sensor based on the dual crosslinked ionogel is assembled, which can be attached to a part of the human body to monitor various motions. Besides that, the wearable sensor can also serve as a fever monitor to indicate the human temperature instantaneously offering promising and strong practicability in wearable electronic devices.

Mechanically toughened conductive hydrogels with shape memory behavior toward self-healable, multi-environmental tolerant and bidirectional sensors

• A toughened, self-healing, anti-freezing, anti-drying, and anti-swelling hydrogel is prepared. • Hydrogel sensors exhibit excellent self-healing capability and multi-environmental stability. • Hydrogel sensors display an attracting feature on distinguishing the direction of human motion. • Hydrogels possess significant shape memory and information storage functions even at −40 °C. Conductive hydrogels have considered as promising materials to revolutionize flexible electronics, biomedical devices and soft robotics. Despite significant progress has been made in the design of hydrogels, simultaneous realization of outstanding mechanical properties, self-healing capability, multi-environmental tolerance (e.g., freezing, drying, water, and oil), and multiple stimuli-responsiveness in a single hydrogel still remains a tremendous challenge. Herein, an extraordinary stretchable (1769%), toughened (0.46 MPa), self-healing, water-retaining (78% after 8 days), anti-freezing (below −40 °C), and anti-swelling (in water/organic solvents) conductive hydrogel is designed and prepared by simultaneously introducing zwitterionic proline, metal ions, and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) into vinyl hybrid silica nanoparticles cross-linked polyacrylic acid networks. Based on this hydrogel, the fabricated strain sensor exhibits excellent strain sensitivity (GF = 3.07), wide sensing range (from 5 to 700%), reliable stability (800 cycles at 200% strain), and accurate human motion detection along two opposite directions (bend down or bend up). In particular, it can not only withstand outstanding mechanical damages but also maintain stable sensing performances in water/organic solvent environments and freezing condition of −40 °C. More interestingly, under FeCl 3 -EG (ethylene glycol) and ascorbic acid-EG solution external stimuli, the resultant hydrogels also display the significant shape memory behaviors and repeated information recording/erasing capabilities even at an extremely cold temperature (−40 °C). These remarkable performances greatly expand the application fields of hydrogels in harsh environments.

Virus-Inspired Gold Nanorod-Mesoporous Silica Core-Shell Nanoparticles Integrated with tTF-EG3287 for Synergetic Tumor Photothermal Therapy and Selective Therapy for Vascular Thrombosis.

Synergetic therapy includes the combination of two or more conventional therapeutic approaches and can be used for tumor treatment by combining the advantages and avoiding the drawbacks of each type of treatment. In the present study, truncated tissue factor (tTF)-EG3287 fusion protein-encapsulated gold nanorod (GNR)-virus-inspired mesoporous silica core-shell nanoparticles (vinyl hybrid silica nanoparticles; VSNP) (GNR@VSNP-tTF-EG3287) were synthesized to achieve synergetic therapy by utilizing selective vascular thrombosis therapy (SVTT) and photothermal therapy (PTT). By integrating the targeted coagulation activity of tTF-EG3287 and the high tumor ablation effect of GNR@VSNP, local hyperthermia could induce a high percentage of apoptosis of vascular endothelial cells by using near-infrared light. This provided additional phospholipid sites for tTF-EG3287 and enhanced its procoagulant activity in vitro. In addition, the nanoparticles, which had unique topological viral structures, exhibited superior cellular uptake properties leading to significant antitumor efficacy. The in vivo antitumor results further demonstrated an interaction between SVTT and PTT, whereas the synergetic therapy (SVTT and PTT) achieved an enhanced effect, which was superior to the respective treatment efficacy of each modality or the additive effect of their individual efficacies. In summary, the synthesized GNR@VSNP-tTF-EG3287 exerted synergetic effects and enhanced the antitumor efficiency by avoiding multiple injections and suboptimal administration. These effects simultaneously affected both tumor blood supply and cancer cell proliferation. The data suggested that the integration of SVTT induced by tTF-EG3287 and PTT could provide potential strategies for synergetic tumor therapy.

Ultra-stretchable, self-adhesive, transparent, and ionic conductive organohydrogel for flexible sensor

Conductive hydrogels are an ideal bio-integrated soft material and show great potential in soft sensors. However, it remains a great challenge to develop an integrated conductive gel combining excellent environmental stability and mechanical properties. Herein, we synthesize a transparent, self-adhesive conductive organohydrogel with excellent environmental stability and UV-blocking performance by constructing multiple cross-links between tannic acid, polyacrylamide, and polyvinyl alcohol. The addition of vinyl hybrid silica nanoparticles can promote dynamic cross-linking of polymer networks and endow organohydrogels with superior mechanical performance (>1800%, 320 kPa). Concurrently, the binary solvent system comprising water and ethylene glycol enables organohydrogels to accommodate different application environments (from −40 °C to 40 °C). Notably, with the incorporation of tannic acid, organohydrogels exhibit lasting and repeatable adhesion (80 kPa), as well as good UV-blocking (>90%). Furthermore, these conductive organohydrogels with great strain sensitivity were used as strain sensors to monitor and distinguish large movements (soft robot movements) and subtle human movements (smiling and electrocardiograph signal) at different temperatures. The conductive organohydrogels have great potential in healthcare monitoring and smart wearable soft electronic devices.

Highly efficient and rapid adsorption of methylene blue dye onto vinyl hybrid silica nano-cross-linked nanocomposite hydrogel

Adsorption treatment of dyes from industrial effluent by hydrogel adsorbent has been a research hotspot, but few high-performance hydrogel adsorbents with high adsorption capacity have been reported. Previously reported poly (acrylic acid) PAA-based hydrogel adsorbents show a low swelling ratio due to the unsatisfactory cross-linked structure, which causes a passive impact on the exhibit of adsorptive sites and the penetration of water inside the hydrogel. Herein, we prepared a novel super-adsorbent nanocomposite (NC) hydrogel adsorbent by employing vinyl hybrid silica nanoparticles (VSNPs) with average diameter of 30 nm as crosslinking agent. The introduction of an optimal content of VSNPs effectively forms a well three-dimensional network structure. The structure system of our NC hydrogel effectively promotes the active sites on the polymer chains to be exposed to dye molecules. Thus, the NC hydrogel adsorbent achieved a high adsorption capacity of 1690 mg/g for adsorbing methylene blue and obtain a high removal ratio of 90 % within 40 min. Furthermore, the hydrogel exhibits excellent reusability after 4 repeated cycles of adsorption and desorption. The work confirmed that the VSNPs can build a well covalent hybrid cross-linked system of a PAA-based hydrogel without other organic crosslinkers and further provided a new method to develop novel hydrogel adsorbent with enhanced adsorption capacity for removing organic dyes from industrial wastewater.

A multifunctional hydrogel polyelectrolyte based flexible and wearable supercapacitor

To well satisfy the newly emerging personalized electronics, it is urgent to develop durable and reliable flexible energy storage devices having a favorable match with them. However, conventional polymer matrixs based hydrogel electrolytes inevitably limit the development of desired supercapacitors due to their poor stretchable, healable as well as electrochemical properties. Here, a novel multifunctional hydrogel polyelectrolyte (VHSNPs-PAA/H2SO4/ARS) is developed comprising the alizarin red S (ARS) redox mediator and the double cross-linked polyacrylic acid (PAA) by the vinyl hybrid silica nanoparticles (VHSNPs) and hydrogen bonds, which realized the combination of ultrahigh stretchability (~2400% strain), robust mechanical toughness (lift up the 500 g weights), favorable self-healability (~92% efficiency during 10 cutting/healing cycles), high ionic conductivity (33 mS cm−1), powerful self-adhesiveness and superior redox activity within a single hydrogel structure. The facilely fabricated carbon-based supercapacitor using the obtained hrdrogel as the electrolyte can achieve large electrode specific capacitance of 248 F g−1 and high mass energy density of 16.7 W h kg−1, which are much larger than the recently reported stretchable and self-healing hydrogel electrolytes based flexible supercapacitors. Meanwhile, as-fabricated device also exhibits the excellent cycling stability and superior durability against physical deformation after 5000 charge-discharge cycles and 200 bending-releasing cycles, respectively.

Reinforced swelling and water-retention properties of super-absorbent hydrogel fabricated by a dual stretchable single network tactic

Super-absorbent hydrogels (SAH) as an advanced material have drew great interest owing to their wide applications in various areas such as forestry, agriculture, sewage treatment and sanitary products. Swelling rate (SR) and water retention ratio (WRR) are usually the pivotal elements for its application. However, high SR of SAH with excellent WRR is rarely reported, which can be mainly due to unsuitable crosslinker. Here we show that a novel SAH with a dual stretchable single network was prepared through a free radical polymerization of AA and AM (acrylic acid-co-acrylic amide) monomer with self-made controllable vinyl hybrid silica nanoparticles (VSNPs) as crosslinker. Particularly, the dual stretchable single network was designed by the molecular chains grafting on the surface of VSNPs and hydrogen bonding on polymer chains, which can significantly improve the cross-linking density and enhance swelling performance. Therefore, SR of the SAH can reach up to 5066 g/g and remain over 70% moisture after exposed to the air for 3 days at 293k with humidity around 50%. This SAH also has an incomparable swelling property in other solution like urea, salt. The adsorption behavior of this SAH matches well with the Fickian diffusion model. Collectively, the design of this work opens a new way for the development of SAH with obviously enhanced swelling performance and water retention capacity in the biomaterial fields.

Self-healing dynamically cross linked versatile polymer electrolyte: A novel approach towards high performance, flexible electrochromic devices

Despite their wide spread implementation, electrochromic (EC) electrolytes based on polymethyl methacrylate, polyvinyl alcohol, polypropylene carbonate lack important properties like self-healing and stretchability which limits their applications for flexible/wearable electrochromic devices (ECD). Here, a dually-crosslinked self-healing polymeric electrolyte P(AA-VIm-VSN) has been synthesized containing acrylic acid (AA), 1-vinylimidazole (VIm) and vinyl hybrid silica nanoparticles (VSN) by copolymerizization process. The cross linking of VSN acts as a stress transfer center to eliminate energy and homogenize the polymer network, thus effectively reinforcing the polymer network under large strain. The dynamically cross-linked hydrogen bonds serve as “non-sacrificial bonds”, which can be effectively recovered on breaking of polymeric network. The novel polymer electrolyte with excellent self-healing ability is important for the development of cost effective, durable and flexible ECD. The resultant gel showed excellent mechanical properties (tensile strength 11 kPa), and noticeable self-healing performance with healing efficiency of 90.5% within 20 min. Simultaneously, a type of hybrid ECD was fabricated containing the self-healing electrolyte with viologen EC materials and polyaniline film counter electrode. The hybrid devices showed well optical contrast (over 45%), fast switching time (2.0 s for coloring and 1.8 s for bleaching), coloration efficiency (406.96 cm2/C) and cyclic stability (>5000 cycles).

Stretchable and Compressible Supercapacitor with Polyaniline on Hydrogel Electrolyte

Flexible and stretchable supercapacitors (SCs) possessing good flexibility, light-weight and portability are important power units for next generation flexible electronics. Herein, we fabricated high-performance stretchable and compressible SCs by in-situ polymerizing polyaniline (PANI) as electrode materials onto both surfaces of the polymer hydrogel electrolyte (PHE) composed of polyacrylic acid crosslinked with vinyl hybrid silica nanoparticles. The PHE-PANI based SCs exhibit excellent electrochemical properties with the areal capacitance of 131 mF/cm2 and cycling stability of 83.7% after 5000 cycles. The devices show outstanding electrochemical performance under both stretching and compressing states. The areal capacitance retention reaches to 162% under 600% stretching and increases slightly under 80% compression strain. A LED lamp can be lit up by three SCs in series in both stretching and compression states. All these results confirm that the PHE-PANI based SC is a promising candidate for novel flexible electronics.

Toughening mechanism of nanocomposite physical hydrogels fabricated by a single gel network with dual crosslinking — The roles of the dual crosslinking points

A facile method to fabricate tough and highly stretchable polyacrylamide (PAM) nanocomposite physical hydrogel (NCP gel) was proposed. The hydrogels are dually crosslinked single network with the PAM grafted vinyl hybrid silica nanoparticles (VSNPs) as the analogous covalent crosslinking points and the reversible hydrogen bonds among the PAM chains as the physical crosslinking points. In order to further elucidate the toughening mechanism of the PAM NCP gel, especially to understand the role of the dual crosslinking points, the PAM hybrid hydrogels (H gels) and a series of poly(acrylamide-co-dimethylacrylamide) (P(AM-co-DMAA)) NCP gels were designed and fabricated. Their mechanical properties were compared with those of the PAM NCP gels. The PAM H gels are prepared by simply mixing the PAM chains with bare silica nanoparticles (SNPs). Relative to the poor mechanical properties of the PAM H gel, the PAM NCP gel is remarkably tough and stretchable and also generates large number of micro-cracks to stop notch propagation, indicating the important role of PAM grafted VSNPs in toughening the NCP gel. In the P(AM-co-DMAA) NCP gels, the P(AM-co-DMAA) chains are grafted on VSNPs and the polydimethylacrylamide (PDMAA) only forms very weak hydrogen bonds between themselves. It is found that mechanical properties of the PAM NCP gel, such as the tensile strength and the elongation at break, are enhanced significantly, but those of the P(AM-co-DMAA) NCP gels decreased rapidly with decreasing AM content. This result reveals the role of the hydrogen bonds among the grafted polymer chains as the physical crosslinking points in toughening the NCP gel.

Phase transition temperature controllable poly(acrylamide-co-acrylic acid) nanocomposite physical hydrogels with high strength

Poly(acrylamide-co-acrylic acid) nanocomposite physical (P(AAm-co-AAc)NCP) hydrogels have been prepared through the in situ free radical solution polymerization based on a “single network, dual cross-linkings” strategy. The P(AAm-co-AAc) NCP hydrogels are composed of nanobrushes of P(AAm-co-AAc) chains grafted on the surface of vinylhybrid silica nanoparticles (VSNPs). In the hydrogel system, the VSNPs act as the “analogous chemical cross-linking points” once the hydrogen bonds formed between the P(AAm-co-AAc) chains of the nanobrushes, thus leading to the fabrication of high-strength P(AAm-co-AAc) NCP hydrogels. Compared with conventional thermosensitive P(AAm-co-AAc) hydrogels, the P(AAm-co-AAc) NCP hydrogels have a broader range of phase transition temperature, which can be adjusted by altering the monomer ratio, the VSNPs concentration, the addition of urea and N,N-dimethylacrylamide (DMAAm). At the same time, the mechanical properties of the P(AAm-co-AAc) NCP hydrogels have been improved significantly by the introduction of VSNPs. Furthermore, both the phase transition and the tensile strength of the P(AAm-co-AAc) NCP hydrogels are largely influenced when Fe3+ ions are introduced as the ionic crosslinkers into the hydrogel networks.

Tough superabsorbent poly(acrylic acid) nanocomposite physical hydrogels fabricated by a dually cross-linked single network strategy

Abstract In this work, we report a facile method for the preparation of tough and highly stretchable physical hydrogels by dual cross-linking composed of vinyl-hybrid silica nanoparticles (VSNPs) as multivalent covalent cross-linking and hydrogen bonding as physical cross-linking. Poly(acrylic acid) nanocomposite physical hydrogels (NCP gels) are obtained without adding any organic chemical cross-linkers. When the content of VSNPs is 0.7 wt% (relative to the monomer), the NCP gels exhibit good mechanical properties (fracture strength = 370 kPa, elongation at break = 2200%) and a high swelling capacity in both deionized water (2300 g/g) and saline (220 g/g). Meanwhile, the NCP gels have good recovery ability.

A self-healable and highly stretchable supercapacitor based on a dual crosslinked polyelectrolyte.

Superior self-healability and stretchability are critical elements for the practical wide-scale adoption of personalized electronics such as portable and wearable energy storage devices. However, the low healing efficiency of self-healable supercapacitors and the small strain of stretchable supercapacitors are fundamentally limited by conventional polyvinyl alcohol-based acidic electrolytes, which are intrinsically neither self-healable nor highly stretchable. Here we report an electrolyte comprising polyacrylic acid dual crosslinked by hydrogen bonding and vinyl hybrid silica nanoparticles, which displays all superior functions and provides a solution to the intrinsic self-healability and high stretchability problems of a supercapacitor. Supercapacitors with this electrolyte are non-autonomic self-healable, retaining the capacitance completely even after 20 cycles of breaking/healing. These supercapacitors are stretched up to 600% strain with enhanced performance using a designed facile electrode fabrication procedure.

Self-healable, tough and highly stretchable ionic nanocomposite physical hydrogels.

We present a facile strategy to synthesize self-healable tough and highly stretchable hydrogels. Our design rationale for the creation of ionic cross-linked hydrogels is to graft an acrylic acid monomer on the surface of vinyl hybrid silica nanoparticles (VSNPs) for the growth of poly(acrylic) acid (PAA), and the obtained VSNP-PAA nanobrush can be used as a gelator. Physical cross-linking through hydrogen bonding and ferric ion-mediated ionic interactions between PAA polymer chains of the gelators yielded ionic nanocomposite physical hydrogels with excellent and balanced mechanical properties (tensile strength 860 kPa, elongation at break ∼2300%), and the ability to self-repair (tensile strength ∼560 kPa, elongation at break ∼1800%). The toughness and stretchability arise from the reversible cross-linking interactions between the polymer chains that help dissipate energy through stress (deformation) triggered dynamic processes. These unique properties will enable greater application of these hydrogel materials, especially in tissue engineering.